Exposure to the "harmful" chemical poses a health risk, causing irritation of the mouth, throat, nose and lungs and in severe cases lead to heart problems, liver and kidney damage and coma, according to Public Health England.

An alert on the FSA website said: "Exposure to xylene in food products represents a health risk as it can cause adverse effects such as headache, dizziness, nausea and vomiting.

"The contaminant levels in this product exceed those set to minimise this risk and the product is therefore being recalled as a precaution."

The products affected are 300g packets of Kania Gravy Granules for meat and for chicken with best before dates of October and November 2017. No other batches are thought to be affected.

The supermarket will display notices in all stores that sold the products, and customers are being urged to return the product for a full refund.